INDEX TO AMERICAN BOTANICAL LITERATURE 421 
Payson, E. B. The North American species of Agquilegia. Contr. 
U.S. Nat. Herb. 20: 133-157. pl. 8-15. 1919. 
Four new species are described. 
Pellegrin, F. Quelques remarques sur les Dioscoréacées du Paraguay. 
Bull. Soc. Bot. Genéve 10: 383-388. 1918. 
Pennell, F. W. Penstemon calycosus. Addisonia 4: 31, 32. pl. 136. 
30 Je 1919. 
Pepoon, H. S. The primrose rocks of Illinois. Trans. Illinois Acad. 
Sci. 10: 159-162. 1917. [Illust.] 
Petch, T. Citrus mildew: a correction. Phytopathology 9: 266. 
24 Je 1919. 
Pipal, F. J. White top and its control. Purdue Univ. Agr. Exp. Sta. 
Circ. 85: 1-12. f. 1-8. D 1918. 
Pring, G. H. Orchids of the Missouri Botanical Garden, St. Louis. 
Mo. Gard. Chron. Am. 23: 208, 209. Je 1919. [Illust.| 
Roberts, H. F. The founders of the art of breeding—II. Jour. 
Heredity 10: 147-152. f. 1 + frontispiece. 26 My 1919. 
Roberts, R. H. ‘‘Crinkle’’ on northwestern greening. Phytopath- 
ology 9: 261-263. pl. 16,17. 24 Je 1919. 
Rock, J. F. Cyrtandreae Hawaiienses, sect. Microcalyces Hillebr. 
Am. Jour. Bot. 6: 203-216. pl. 29-32. My 1919. 
Cyrtandra Giffardii, C. limosiflora, C. montis Loa, C. ramosissima, and C. Hashi- 
motoi, spp. nov., are described wee 
Sayre, J. D. Comparative transpiration of tobacco and mullein. 
Ohio Jour. Sci. 19: 422-426. f. 1. My 1919. 
Schaffner, J. H. The nature of the dioecious condition in Morus alba 
and Salix amygdaloides. Ohio Jour. Sci. 19: 409-416. My 1919. 
Schmitz, H. Studies in the physiology of the fungi—VI. The 
relation of bacteria to cellulose fermentation induced by fungi, 
with special reference to the decay of wood. Ann. Missouri Bot. 
Gard. 6: 93-136. Ap Igig. 
Selby, A. D. Apple blotch, a serious fruit disease. Bull. Ohio Agr. 
Exp. Sta. 333: 491-505. f. 1-5. F 1919. 
Seward, A.C. Recent paleobotany in Great Britain. Science II. 50: 
43-48. 11 Je 1919. 
Small, J. K. Heliotropium Leavenworthii. Addisonia 4: 29, 30. 
pl. 135. 30 Je 1919. 
Small, J. K. Heliotropium polyphyllum. Addisonia 4: 25, 26. pl. 133- 
30 Je 1919. 
